Different hand dryers are known today which have a drying chamber so that the user can insert his or her hands therein and dry them, said drying chamber having outlets for projecting air on the user's hands.
Patent document JP2000245652 discloses a hand dryer having a drying chamber tilted towards the front area for inserting the user's hands and provided with air outlet orifices arranged in the side and upper walls of said drying chamber. Said orifices are connected by means of multiple ducts to a blower propelling the air towards said outlets. The side and upper arrangement of the outlets prevents the projected air from simultaneously acting on the obverse and reverse sides of two hands, requiring the user to change his or her hands from their position in order to completely dry them.
Patent document JP2002034847 discloses a hand dryer having a drying chamber closed on all its sides and provided with an upper mouth for inserting the user's hands. Said drying chamber has in opposite front and back walls respective rows of air outlet orifices, requiring the user to move his or her hands during drying so that the supplied air can act on different areas of his or her hands, prolonging drying time. The air projected through the two rows of orifices is supplied by a single ventilator and guided through a single inner chamber towards the two opposite sides of the dryer, which causes the airflow to split and changes in direction, generating significant pressure drops in the air conduction and an outlet speed reduction.
Patent document DE548998 discloses a hand dryer having a considerably spherical drying chamber open at one of its ends and inside of which two nozzles are arranged in opposite positions that are responsible for projecting the air onto the user's hands inserted in the aforementioned chamber.
In this patent the nozzles or outlets have a small surface, requiring the user to move his or her hands inside the chamber in order to dry them. In addition, the vertical orientation of the air nozzles or outlets necessitates that the hands be inserted inside the chamber in a considerably horizontal position, preventing the force of gravity from assisting the air outlets in eliminating the water existing on the user's hands.
In patent document GB2249026 discloses a hand dryer with a chamber for inserting the user's hands. Said chamber has in one of its sides an elongated air outlet opening in the shape of a blade, said opening being connected to an air supply duct by means of an enveloping hollow surrounding the aforementioned drying chamber.
In this patent, the elongated shape of the air outlet opening determines that the projected air blade or curtain acts on a small surface of the hand inserted in the drying chamber, requiring the user to move his or her hand inside the aforementioned chamber to effectively dry the entire surface of his or her hand.
Patent document U.S. Pat. No. 4,336,619 discloses a hand washing and drying device having a working enclosure or chamber tilted towards the lower back area and provided with a mouth in the upper front area for inserting the hands to be washed and dried. Said chamber has an orifice at the upper portion for the outlet of the water required to wash hands and an air outlet in which propulsion means are associated, forming a dryer strictly speaking.
In this patent the user must insert his or her hands inside the chamber in order to wash and then dry them, the projection of the air on the hands being done in the same way as in the previously discussed patents, in virtually a very localized manner, requiring the user to move his or her hands inside the chamber in order to completely dry them, this operation involving an excessive time.
Patent document EP0589568 discloses a hand dryer having a hand insertion unit which is tilted towards the lower back area and open towards the upper front area and the sides, said hand insertion unit having outlets in the two front and back faces provided with respective alignments of orifices for projecting respective air curtains on the obverse and reverse sides of the user's hands inserted in a tilted position inside the drying unit.
In this case, like in the aforementioned patent document U.S. Pat. No. 4,336,619 the user's hands are inserted in the drying unit in a tilted position, therefore gravity has little effect on eliminating the water deposited on the hands towards the lower area of the chamber. Also with the described embodiment, in patent EP0589568 the projection of air on the user's hands is done in localized areas, requiring the user to move his or her hands inside the drying unit so that the air can act on different areas of his or her hands.
In some of the mentioned documents the projection of air on the hands is done at high pressure, being propelled by turbines connected to the mentioned outlets by means of pipes generating turbulences in the circulating air and considerably reducing the air outlet speed towards the drying chamber or unit.
One of the mentioned dryers also has at the bottom of the drying chamber or unit a drain pipe for draining the water released by the user's hands towards a drain (U.S. Pat. No. 4,336,619) or towards a water collection tray (EPO589568), this second case requires manually emptying the water collection tray on a rather frequent basis.
If this tray is not emptied as frequently as it should be, the water accumulated therein will end up overflowing and falling towards the lower area, with the subsequent risk of damage to the dryer and of spilling onto the user.